<template>
  <div class="goods-image">
    <!-- 放大镜图 -->
    <div v-show="show" class="large" :style="[{ backgroundImage: `url(${images[currIndex]})` },bgPositio]"></div>
    <!-- 左侧大图 -->
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="">
      <!-- 遮罩层 -->
      <div v-show="show" class="layer" :style="position"></div>
    </div>
    <!-- 右侧图 -->
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex = i" :src="img" alt="">
      </li>
    </ul>
  </div>
</template>
<script>
import { reactive, ref, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
export default {
  name: 'GoodsImage',
  props: {
    images: {
      type: Array,
      default: () => []
    }
  },
  setup(props) {
    //当前图片的索引
    const currIndex = ref(0)

    //1.是否展示遮罩层以及放大后的图
    const show = ref(false)
    //2.遮罩层的坐标
    const position = reactive({
        left:0,
        top:0
    })
    //3.放大图的坐标
    const bgPositio = reactive({
      backgroundPositionX:0,
      backgroundPositionY:0
    })
    //4.使用vueuse工具提供的useMouseInElement方法
    const target = ref(null)
    const {elementX,elementY,isOutside} = useMouseInElement(target)
    
    watch([elementX,elementY,isOutside],()=> {
      //是否显示遮罩层
      show.value = !isOutside.value
      //计算坐标
      const newposition = {
        x:0,
        y:0
      }
      if(elementX.value < 100) {
        newposition.x = 0
      }else if(elementX.value > 300) {
        newposition.x = 200
      }else{
        newposition.x = elementX.value - 100
      }
      if(elementY.value < 100) {
        newposition.y = 0
      }else if(elementY.value > 300) {
        newposition.y = 200
      }else{
        newposition.y = elementY.value - 100
      }
      //赋值
      position.left = newposition.x + 'px'
      position.top = newposition.y + 'px'
      bgPositio.backgroundPositionX = - newposition.x*2 + 'px'
      bgPositio.backgroundPositionY = - newposition.y*2 + 'px'
    })
    return { 
      currIndex,
      show,
      position,
      bgPositio,
      target
    }
  }
}
</script>
<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;

    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, .2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>